I'm looking to purchase my first set of grow lights off craigslist and I'm wondering what the difference between a "grow light" and a ballast is. Is the ballast a part of the actual grow light or does it come sperately?
The term "grow light" includes everything..hood/reflector, bulb, and ballast. Ballast regulates the electrical current so your light doesn't draw too much electricity and burn out.
It's what @[member="lFourTwenty"] said but be careful when someone refers to it as a "grow light". This can mean anything and doesn't even mean it's suitable for what you want it for. I have seen an incandescent bulb labelled as a grow light before